Quick Answer
The answer is `chmod u+x script.sh`. This command is correct because the script’s current permissions, `-rw-r--r--`, grant the owner read and write access but not execute permission, so adding the execute bit for the user only (`u+x`) directly resolves the “Permission denied” error without altering permissions for the group or others. On the Linux Foundation Certified System Administrator LFCS exam, this tests your understanding of symbolic permission notation and the principle of least privilege—a common trap is using `chmod +x` alone, which adds execute for all three categories, potentially over-permitting the file. A reliable memory tip is to think “u+x” as “user eXecute only,” keeping the script secure while functional.
This LFCS practice question tests your understanding of essential commands. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A user reports that a script fails with 'Permission denied' when executed. The script has permissions -rw-r--r-- and is owned by the user. Which command should the user run to make the script executable for the owner only?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "which command"
Why it matters: Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.
chmod u+s script.sh
Why wrong: Sets the setuid bit, not execute.
chmod u+x script.sh
Adds execute permission for the owner only.
chown :users script.sh
Why wrong: Changes group ownership, not permissions.
chmod +x script.sh
Why wrong: Adds execute for all users, not just owner.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
chmod u+x script.sh
Option B is correct because the script currently has permissions `-rw-r--r--`, meaning the owner has read and write but not execute permission. The `chmod u+x` command adds the execute permission for the owner only, which is exactly what the user needs to run the script without affecting group or others.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
chmod u+s script.sh
Why it's wrong here
Sets the setuid bit, not execute.
chmod u+x script.sh
Why this is correct
Adds execute permission for the owner only.
Clue confirmation
The clue word "which command" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
chown :users script.sh
Why it's wrong here
Changes group ownership, not permissions.
chmod +x script.sh
Why it's wrong here
Adds execute for all users, not just owner.
Common exam traps
The trap here is that candidates may confuse the setuid bit (`u+s`) with the execute bit (`u+x`), or assume that `chmod +x` is equivalent to `chmod u+x`, when in fact the former grants execute to all users, which is not what the question asks.
Detailed technical explanation
In Linux file permissions, the execute bit (x) is required to run a file as a command or script. The `chmod` command uses symbolic mode (e.g., `u+x`) to modify permissions for specific user classes: owner (u), group (g), others (o), or all (a). Without the execute bit, the kernel's `execve()` system call will return EACCES, even if the file is owned by the user. A common real-world scenario is when a script is downloaded or created with default umask settings that omit the execute bit.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A practitioner preparing for the LFCS exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Essential Commands — This question tests Essential Commands — Read the scenario before looking for a memorised answer..
The correct answer is: chmod u+x script.sh — Option B is correct because the script currently has permissions `-rw-r--r--`, meaning the owner has read and write but not execute permission. The `chmod u+x` command adds the execute permission for the owner only, which is exactly what the user needs to run the script without affecting group or others.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Yes — watch for: "which command". Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 11, 2026
This LFCS practice question is part of Courseiva's free Linux Foundation certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the LFCS exam.
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